Hyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults.

2.50
Hdl Handle:
http://hdl.handle.net/2436/620473
Title:
Hyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults.
Authors:
Kenny, Glen P; Poirier, Martin P; Metsios, George S.; Boulay, Pierre; Dervis, Sheila; Friesen, Brian J; Malcolm, Janine; Sigal, Ronald J; Seely, Andrew J E; Flouris, Andreas D
Abstract:
We examined whether older individuals experience greater levels of hyperthermia and cardiovascular strain during an extreme heat exposure compared to young adults. During a 3-hour extreme heat exposure (44°C, 30% relative humidity), we compared body heat storage, core temperature (rectal, visceral) and cardiovascular (heart rate, cardiac output, mean arterial pressure, limb blood flow) responses of young adults (n = 30, 19-28 years) against those of older adults (n = 30, 55-73 years). Direct calorimetry measured whole-body evaporative and dry heat exchange. Body heat storage was calculated as the temporal summation of heat production (indirect calorimetry) and whole-body heat loss (direct calorimetry) over the exposure period. While both groups gained a similar amount of heat in the first hour, the older adults showed an attenuated increase in evaporative heat loss (p < 0.033) in the first 30-min. Thereafter, the older adults were unable to compensate for a greater rate of heat gain (11 ± 1 ; p < 0.05) with a corresponding increase in evaporative heat loss. Older adults stored more heat (358 ± 173 kJ) relative to their younger (202 ± 92 kJ; p < 0.001) counterparts at the end of the exposure leading to greater elevations in rectal (p = 0.043) and visceral (p = 0.05) temperatures, albeit not clinically significant (rise < 0.5°C). Older adults experienced a reduction in calf blood flow (p < 0.01) with heat stress, yet no differences in cardiac output, blood pressure or heart rate. We conclude, in healthy habitually active individuals, despite no clinically observable cardiovascular or temperature changes, older adults experience greater heat gain and decreased limb perfusion in response to 3-hour heat exposure.
Citation:
Hyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults. 2017, 4 (1):79-88 Temperature (Austin)
Publisher:
Taylor & Francis
Journal:
Temperature (Austin, Tex.)
Issue Date:
2017
URI:
http://hdl.handle.net/2436/620473
DOI:
10.1080/23328940.2016.1230171
PubMed ID:
28349096
Additional Links:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5356213/
Type:
Article
Language:
en
ISSN:
2332-8940
Appears in Collections:
FEHW

Full metadata record

DC FieldValue Language
dc.contributor.authorKenny, Glen Pen
dc.contributor.authorPoirier, Martin Pen
dc.contributor.authorMetsios, George S.en
dc.contributor.authorBoulay, Pierreen
dc.contributor.authorDervis, Sheilaen
dc.contributor.authorFriesen, Brian Jen
dc.contributor.authorMalcolm, Janineen
dc.contributor.authorSigal, Ronald Jen
dc.contributor.authorSeely, Andrew J Een
dc.contributor.authorFlouris, Andreas Den
dc.date.accessioned2017-05-10T15:44:57Z-
dc.date.available2017-05-10T15:44:57Z-
dc.date.issued2017-
dc.identifier.citationHyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults. 2017, 4 (1):79-88 Temperature (Austin)en
dc.identifier.issn2332-8940en
dc.identifier.pmid28349096-
dc.identifier.doi10.1080/23328940.2016.1230171-
dc.identifier.urihttp://hdl.handle.net/2436/620473-
dc.description.abstractWe examined whether older individuals experience greater levels of hyperthermia and cardiovascular strain during an extreme heat exposure compared to young adults. During a 3-hour extreme heat exposure (44°C, 30% relative humidity), we compared body heat storage, core temperature (rectal, visceral) and cardiovascular (heart rate, cardiac output, mean arterial pressure, limb blood flow) responses of young adults (n = 30, 19-28 years) against those of older adults (n = 30, 55-73 years). Direct calorimetry measured whole-body evaporative and dry heat exchange. Body heat storage was calculated as the temporal summation of heat production (indirect calorimetry) and whole-body heat loss (direct calorimetry) over the exposure period. While both groups gained a similar amount of heat in the first hour, the older adults showed an attenuated increase in evaporative heat loss (p < 0.033) in the first 30-min. Thereafter, the older adults were unable to compensate for a greater rate of heat gain (11 ± 1 ; p < 0.05) with a corresponding increase in evaporative heat loss. Older adults stored more heat (358 ± 173 kJ) relative to their younger (202 ± 92 kJ; p < 0.001) counterparts at the end of the exposure leading to greater elevations in rectal (p = 0.043) and visceral (p = 0.05) temperatures, albeit not clinically significant (rise < 0.5°C). Older adults experienced a reduction in calf blood flow (p < 0.01) with heat stress, yet no differences in cardiac output, blood pressure or heart rate. We conclude, in healthy habitually active individuals, despite no clinically observable cardiovascular or temperature changes, older adults experience greater heat gain and decreased limb perfusion in response to 3-hour heat exposure.en
dc.language.isoenen
dc.publisherTaylor & Francisen
dc.relation.urlhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC5356213/en
dc.rightsArchived with thanks to Temperature (Austin, Tex.)en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.subjectagingen
dc.subjectcalorimetryen
dc.subjectclimate changeen
dc.subjectextreme heat eventsen
dc.subjectheat stressen
dc.titleHyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults.en
dc.typeArticleen
dc.identifier.journalTemperature (Austin, Tex.)en
dc.date.accepted2016-08-25-
rioxxterms.funderinternalen
rioxxterms.identifier.projectUOW100517GMen
rioxxterms.versionVoRen
rioxxterms.licenseref.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/en
rioxxterms.licenseref.startdate2017-05-10en

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